/*
 * Copyright (C) 2009 Kristopher T Babic
 *
 * This program is free software; you can redistribute it and/or modify it under the terms of
 * the GNU General Public License as published by the Free Software Foundation; either
 * version 3 of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
 * without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 * See the GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along with this program;
 * if not, see <http://www.gnu.org/licenses>.
 */

package edu.idp.shared.net;

/**
 *
 */
public class BusyFlag {
    protected Thread busyflag = null;
    protected int busycount = 0;

    public void getBusyFlag() {
        while (tryGetBusyFlag() == false) {
            try {
                wait();
            }
            catch (Exception e) {
            }
        }
    }

    protected synchronized boolean tryGetBusyFlag() {
        if (busyflag == null) {
            busyflag = Thread.currentThread();
            busycount = 1;
            return true;
        }
        if (busyflag == Thread.currentThread()) {
            busycount++;
            return true;
        }
        return false;
    }

    public synchronized void freeBusyFlag() {
        if (getBusyFlagOwner() == Thread.currentThread()) {
            busycount--;
            if (busycount == 0) {
                busyflag = null;
                notify();
            }
        }
    }

    public synchronized Thread getBusyFlagOwner() {
        return busyflag;
    }
}
